Preventing froth on paper machines



April 7, 1925.

' W. E. METCALF PREVENTING FROTH ON PAPER MACHINES V a ll Hm,

. Max m Filed Dec. 23, 1922 Inventor:-

Walter EMeZeaQ/Z' 4' WW;

dud/Ja Aug].

' the formation of mats orclots.

fibres not Patented Apr. 7, 1925.

UNITED STATES PATENT OFFICE.

WALTER METCALF, OF HUDSON FALLS, NEW YORK, ASSIGNOR TO PROCESS ENGI- NEERS, 1116., OF NEW XORCK, N. Y.

PREVENTING FROTH ON PAPER MACHINES.

Application filed December 23, 1922. Serial No. 608,724.

Toazll whom it may concern.

Be it known that I, WALTER E. METoALr, a citizen of the United States, residing at Hudson Falls, New York, have invented certain new and useful Improvements in Preventing F roth on Paper Machines, of which the following is a specification.

This invention relates to a method of distribution of paper pulp in the process of producing paper, by either the cylinder or Fourdrinier wire mediums, so that a uniform thickness of fibres will obtain without By practicing this method, the usual frothing in the head box is eliminated.

In the manufacture of paper, it is generally necessary to screen the stock in a very dilute condition before it flows to the wire which picks up the fibres and forms a' sheet of paper.

The common method of doing this, is to allow the screened pulp to flow direct from the screen into a sluice box, and from there to a head box where the motion flow is' allowed to subside.

From the head box it flows slowly onto the wire where it is picked up by the motion of either the Fourdrinier .wire or cylinder mold. depending upon the type of machine that is used.

I have discovered certain disadvantages in this method of operation; first, a tendency towards production of froth, by allowing the stock to splash into the head box from the screens.

I have also discovered that the subsiding of the flow which takes place in the head box, allows the fibres to gather together in such as will always occur with in motion. The result of this is that the stock flowing from the ordinary head box onto the wire, does not contain fibres uniformly dispersed throughout the water through which they are suspended, but a series of clots or masses of fibres which, when formed into paper, give it a cloudy appearance.

Nearly all paper which has a bad formation, is made from fibres which were not in motion when they came in contact with the wire, but had time to adhere to other fibres in relatively large bundles, the fibres being concentrated in certain portions of the liquid.

The object of my invention is to provide a means for transferring the screened fibres bunches,

from the screens to the head box, without and not in bunches as is ordinarily the case.

I have illustrated diagrammatically, apparatus for the production of paper carry-'- ing out the principles of this invention. While I have found certain steps of value, at this time, it is understood that they are merely preferred now, and I do not wish to be limited entirely thereto.

In these drawings Figure 1 is a diagrammatic view of a portion of a paper plant in side elevation.

Fig. 2 is a plan view of Fig. 1.

My method of obtaining this result, is to allow the water and fibres from the screen 1 to pass into a flow box 2, which carries it to a central box 3 from which it is taken by a pump 4 and carried within a pipe 5 directly into the head box 6. The end of this pipe is submerged in the head box and discharges into a horizontal pipe 7 containing various orifices 8 through which the stock is dis charged in fine streams in various directions. These many streams of rapidly flowing stock keep the fibres in motion in every direction, but being discharged beneath the surface, do not produce any froth. By agitating the stock in the head box in the above manner, the individual fibres are in motion when they reach the wire, and there is no trouble in getting the proper formation of fibres on the wire. 1

My invention consists primarily in means for keeping the individual fibres in motion within the head box, so that they will be uniformly distributed throughout the aqueous medium in which they are suspended when they are picked up by the wire.

This invention applies equally to cylinder machines as well as to Fourdrinier machines.

into the head box under considerable velocity through the orifices in' the horizontal plpe. From this point the fibres pass to the breast roll in the usual manner.

I claim as my invention i In apaper machine, a head box, a flow box, a central box connected therewith, and a screen, a pipe terminating in a head having orifices therein submerged in said head box,

baflles in said head box, and pump means for 10 forcing water and fibres from said central box through said ipe and expelling the same through said ori ces below the level of the liquid in said head box.

In testimony whereof I have afiixed my 15 signature to this specification.

WALTER; METCALF. 

